This invention relates to a process for producing a polymer of monoallylamine (CH.sub.2 .dbd.CH--CH.sub.2 NH.sub.2).
As is well known, allyl compounds are difficult to polymerize with usual radical initiators and they only yield polymers having a low degree of polymerization in low yield.
This is explained as being due to the occurrence of the self-termination reaction between allylic hydrogen atoms and radicals, and this reaction is usually called "allylic degradative chain transfer".
This fact is a common knowledge of polymer chemists, and is mentioned in many papers and textbooks [cf. for example, C. E. Schildknecht, Allyl Compounds and their Polymers, Willey-Interscience, 1973, pp. 29-30; and R. C. Laible, Chem. Rev. 58, (5), 807-843 (1958)].
Such is unexceptionally applicable also to monoallylamine which is a kind of allyl compound. Thus, monoallylamine hardly polymerizes with radical or ionic initiators, and only a few examples of polymerization have been reported in which the polymerization takes place under the following special conditions (pp. 523-524 of the above-mentioned textbook):
(1) The process of obtaining a brown-colored resinous polymonoallylamine (hereinafter simply referred to as "polyallylamine") by gas phase polymerization using tetrafluorohydrazine as a catalyst (U.S. Pat. No. 3,062,798);
(2) The process of obtaining a black-brown colored, resinous polyallylamine having a molecular weight of 950-1,000 by adding a small amount of water to monoallylamine hydrochloride to bring it into a state of aqueous melt and then polymerizing it at 80.degree.-85.degree. C. while adding hydrogen peroxide in small portions [V. V. Zycova et al., Tr. Inst. Khim. Nauk, Akad. Nauk Kaz. SSR 11, 89-94 (1964); Chem. Abst. 61. 14855 (1964)].
The above-mentioned processes 1 and 2 are examples of polymerization of monoallylamine in which catalysts such as radical initiators are used. However, in both examples, no polymer having a high degree of polymerization is obtained.
The following radiation polymerization processes have also been proposed as processes for polymerizing monoallylamine. The monoallylamine polymers obtained monoallylamine. The monoallylamine polymers obtained by these processes have a higher degree of polymerization than that of the polymers obtained by the processes using radical type catalysts.
(3) The process of polymerizing monoallylamine in a protic acid (sulfuric acid, phosphoric acid or hydrochloric acid) while irradiating it with gamma rays or while irradiating it with ultraviolet rays in the presence of hydrogen peroxide [V. A. Kabanov et al., Vysokomol. Soed., 18, No. 9, 1957-1962 (1976); 18, No. 10, 2233-2238 (1976)].
(4) The process of irradiating monoallylamine, allyl cyanide or allylmercaptan with a variety of radiations (gamm rays, electron beams, X rays, ultraviolet rays) in the presence of an inorganic acid or an inorganic acid salt of a metal belonging to Group I or II of the periodic table (L. S. Polak, V. A. Kabanov et al., USSR Pat. No. 296,423). Though this USSR patent includes polymerization processes using radical type catalysts, examples in the patent include no case of polymerizing monoallylamine with a radical type catalyst, only referring to a process of polymerizing allyl cyanide with benzoyl peroxide in the presence of zinc chloride and a process of polymerizing allylmercapton with hydrogen peroxide in the presence of calcium chloride.
On the other hand, since polyallylamine is a quite interesting polymer, there have been made attempts to produce polyallylamine or its N-alkyl-substituted derivatives by the chemical modification of other vinyl polymers. As examples of such attempts, the followings can be referred to:
(5) The process of producing polyallylamine by hydrogenating polyacrylonitrile latex (U.S. Pat. No. 2,456,428);
(6) The process of synthesizing polyallylamine by the reduction of polyacrolein-oxime [Yoshikazu Hatsuhama et al., Kogyo Kagaku Zasshi 64, No. 3,595 (1961)];
(7) The process of obtaining a polymer of allyltrimethylammonium chloride by reacting an allyl chloride polymer having a molecular weight of about 900 with trimethylamine (U.S. Pat. No. 4,053,512); and
(8) A process of producing poly-(N,N-dimethylallylamine) by reducing a polymer of N,N-dimethylacrylamide (the same patent as above).
Among the eight processes for producing monoallylamine polymer mentioned above, the radiation polymerization processes with gamma rays in protic solvents mentioned in 3 to 4 are relatively preferable. As is well known, however, radiation polymerization is not the best process for producing a large amount of polymer, and at the present stage there is no case of industrially producing a polymer by the radiation polymerization process. Thus, polyallylamine is not produced industrially even today, whereas monoallylamine has been industrially produced from many years ago.